The invention relates to an oil reservoir simulation method. The method relates to a region division device, a mesh generation device, a mapping device, an interface processing device and a matrix construction device and a matrix solving device, wherein the region division device is used for dividing an oil reservoir into multiple regions, and the multiple regions at least include a component region and a black oil region; the mesh generation device is used for mesh generation of each region and forming interfaces between the regions; the mapping device is used for mapping the component region and the black oil region to intermediary material to establish correlation; the interface processing device is used for processing the interfaces according to the law of conservation of mass; the matrix construction device is used for constructing a uniform matrix according to the mapping results of the multiple regions and the interface processing results; the matrix solving device is used for solving the uniform matrix. Through the method, data can be exchanged between different regions in real time in simulation, discontinuity of fluid between the regions is eradicated, simulation efficiency can also be improved, and the expansibility of a following simulator is improved.